U.S. patent application number 10/912132 was filed with the patent office on 2005-03-03 for foamable compositions which comprise isononyl benzoate.
This patent application is currently assigned to DEGUSSA AG. Invention is credited to Grass, Michael, Koch, Jurgen.
Application Number | 20050049341 10/912132 |
Document ID | / |
Family ID | 33547122 |
Filed Date | 2005-03-03 |
United States Patent
Application |
20050049341 |
Kind Code |
A1 |
Grass, Michael ; et
al. |
March 3, 2005 |
Foamable compositions which comprise isononyl benzoate
Abstract
Compositions for producing foamed products which comprise a
chlorinated polymer such as PVC and at least one isomeric nonyl
benzoate as a plasticizer, the use of these compositions, and
products produced therefrom including PVC-containing
floorcoverings, synthetic leather, and wallcoverings.
Inventors: |
Grass, Michael; (Haltern am
See, DE) ; Koch, Jurgen; (Haltern am See,
DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
DEGUSSA AG
Duesseldorf
DE
D-40474
|
Family ID: |
33547122 |
Appl. No.: |
10/912132 |
Filed: |
August 6, 2004 |
Current U.S.
Class: |
524/306 ;
524/315 |
Current CPC
Class: |
C08J 9/0014 20130101;
C08J 2327/02 20130101; C08K 5/10 20130101 |
Class at
Publication: |
524/306 ;
524/315 |
International
Class: |
C08K 005/09 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 7, 2003 |
DE |
103 36 150.2 |
Claims
1. A foamable composition comprising at least one chlorinated
polymer, at least one alkyl benzoate, and at least one primary
plasticizer; wherein isononyl benzoate is present in an amount of
from 5 to 95% by weight based on the total weight of the primary
plasticizers and the alkyl benzoates, and wherein the total weight
of the primary plasticizers and the alkyl benzoates is from 10 to
400 parts by weight based on 100 parts by weight of the chlorinated
polymers.
2. The composition as claimed in claim 1, wherein the chlorinated
polymer is at least one selected from the group consisting of
polyvinyl chloride, polyvinylidene chloride, chlorinated
polyolefin, vinyl chloride-vinylidene chloride copolymer, vinyl
acetate-vinyl chloride copolymer, vinyl propionate-vinyl chloride
copolymer, vinyl butyrate-vinyl chloride copolymer, vinyl
benzoate-vinyl chloride copolymer, methyl acrylate-vinyl chloride
copolymer, ethyl acrylate-vinyl chloride copolymer, and butyl
acrylate-vinyl chloride copolymer.
3. The composition as claimed in claim 1, comprising one or more of
an alkyl phthalate, an alkyl cyclohexanedicarboxylate, or an alkyl
adipate.
4. The composition as claimed in claim 1, comprising at least one
alkyl phthalate selected from the group consisting of diisononyl
phthalate, diisoheptyl phthalate, and di-2-ethylhexyl
phthalate.
5. The composition as claimed in claim 1, comprising diisononyl
cyclohexanedicarboxylate.
6. The composition as claimed in claim 1, comprising diisononyl
adipate.
7. The composition as claimed in claim 1, comprising at least one
selected from the group consisting of diisononyl phthalate,
diisoheptyl phthalate and di-2-ethylhexyl phthalate; diisononyl
cyclohexanedicarboxylate; and diisononyl adipate.
8. The composition as claimed in claim 1, further comprising at
least one additive selected from the group consisting of a filler,
a pigment, a heat stabilizer, an antioxidant, a viscosity
regulator, a foam stabilizer, and a lubricant.
9. The composition as claimed in claim 1, further comprising a
component which generates gas bubbles.
10. The composition as claimed in claim 9, further comprising a
kicker.
11. The composition as claimed in claim 1, comprising an emulsion
PVC.
12. The composition as claimed in claim 1, comprising PVC and
diisobutyl phthalate.
13. The composition as claimed in claim 12, further comprising one
or more of a filler, titanium dioxide or a release agent.
14. The composition of claim 11, further comprising at least one
glycol dibenzoate.
15. The composition of claim 11, further comprising at least one
alkyl benzyl phthalate.
16. A product comprising a foamed layer obtained by foaming the
composition of claim 1.
17. The product as claimed in claim 16, which is a floor covering,
a wall covering, or a synthetic leather.
18. A process for producing a product having a foamed chlorinated
polymer layer comprising at least one chlorinated polymer, at least
one primary plasticizer and at least one alkyl benzoate; wherein
isononyl benzoate is present in the foamed chlorinated polymer
layer in an amount of from 5 to 95% by weight based on the total
weight of the primary plasticizers and the alkyl benzoates, and the
total weight of the primary plasticizers and the alkyl benzoates is
from 10 to 400 parts by weight based on 100 parts by weight of the
chlorinated polymers, said process comprising applying the
composition as claimed in claim 1 to a backing, foaming the
composition prior to or after application, and then heating the
applied and foamed composition.
19. The process as claimed in claim 18, wherein the chlorinated
polymer layer is at least one selected from the group consisting of
polyvinyl chloride, polyvinylidene chloride, chlorinated
polyolefin, vinyl chloride-vinylidene chloride copolymer, vinyl
acetate-vinyl chloride copolymer, vinyl propionate-vinyl chloride
copolymer, vinyl butyrate-vinyl chloride copolymer, vinyl
benzoate-vinyl chloride copolymer, methyl acrylate-vinyl chloride
copolymer, ethyl acrylate-vinyl chloride copolymer, and butyl
acrylate-vinyl chloride copolymer
20. A foamed product obtained by the process as claimed in claim
19.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to foamable compositions which contain
polyvinyl chloride and isononyl benzoate (INB), and to a process
for preparing a foamed PVC product and products containing or
derived from the foamable composition.
[0003] 2. Description of the Related Art
[0004] Polyvinyl chloride (PVC) is an important commercial polymer.
It is used in a wide variety of applications, including in the form
of rigid PVC and in the form of plasticized PVC.
[0005] Plasticizers are added to PVC to produce a plasticized
polymer. The plasticizer is in many cases a phthalic ester, in
particular di-2-ethylhexyl phthalate (DEHP), diisononyl phthalate
(DINP), or diisodecyl phthalate (DIDP). As the chain length of the
ester increases, the solvation or gelling temperature of the
plasticizer rises and the processing temperature of the plasticized
PVC therefore also rises. The processing temperature can in turn be
reduced by adding a fast-geller, such as a short-chain phthalate
such as, for example, di-n-butyl phthalate (DBP), diisobutyl
phthalate (DIEP), benzyl butyl phthalate (BBP), or diisoheptyl
phthalate (DIHP). Dibenzoic esters, such as dipropylene glycol
dibenzoate or the like may be added for the same purpose.
[0006] A marked rise in viscosity over time is a property
frequently exhibited by these fast-geller plasticizers in PVC
plastisols due to their high solvating power. In many cases the
viscosity rise has to be compensated for by adding (often
expensive) viscosity-reducers.
[0007] When PVC plastisols are prepared, the general requirement is
low viscosity and minimum gelling temperature. In addition, high
storage stability (e.g., a low rise in viscosity of the plastisol
over time) is desirable.
[0008] High viscosity may be disadvantageous during processing of
the plastisol on machinery (such as spreading or dipping).
Excessively high gelling temperature may lead to discolorations due
to thermal stress.
[0009] Currently there are few plasticizers which significantly
lower the gelling temperature in a plastisol formulation while
retaining a low level of viscosity especially after storage for a
number of days. 2-Ethylhexyl benzoate was recently proposed as a
product which could fulfill these requirements [Bohnert, Stanhope,
J. Vinyl Addit. Technol. (2000), 6(3), 146-149]. However, this
compound has a comparatively high vapor pressure, which often leads
to unacceptable losses of the plasticizer during processing, and to
comparatively high emissions during use.
[0010] WO 01/29140 discloses the use of benzoic esters of C.sub.8
alcohols in film-forming compositions.
[0011] U.S. Pat. No. 5,236,987 describes the use of benzoates
derived from C.sub.8-C.sub.12 alcohols in plastisols. The use of
these compounds by way of example in latex formulations is also
described.
[0012] DE 19 62 500 discloses compositions which comprise a vinyl
polymer and one or more esters of benzoic acid with a
C.sub.8-C.sub.13 alcohol, and also, where appropriate, succinic
esters. These compositions are used to produce polymer films.
[0013] WO 97/39060 describes plastisols which comprise, as
plasticizer, a benzoate of a C.sub.11-C.sub.14 alcohol. These
plasticizers are used inter alia in plastisols to produce foams,
but no improvement of foam structure was found when comparison was
made with conventional plastisols. Nor was any significant decrease
of gelling temperature found in blends with DINP.
SUMMARY OF THE INVENTION
[0014] Accordingly, it is an object of the present invention to
provide compositions for forming foamed layers which comprise homo-
or copolymers of vinyl chloride and/or of polyvinylidene
dichloride, and/or of chlorinated polyethylene, and an alkyl
benzoate which significantly lower both the viscosity and the
gelling temperature of the composition, generally a plastisol, and
thus permit easier and faster processing. In addition, the alkyl
benzoate may be derived from minimum-cost raw materials.
[0015] Surprisingly, it has been found that foamable compositions
which comprise at least one polymer selected from polyvinyl
chloride, polyvinylidene chloride, chlorinated polyolefins, and
copolymers of vinyl chloride with vinylidene chloride, vinyl
acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, methyl
acrylate, ethyl acrylate, butyl acrylate, and which comprise at
least one primary plasticizer, and an isononyl benzoate are capable
of easy and rapid processing.
[0016] In one embodiment, the present invention provides foamable
compositions for producing foamed products, comprising at least one
polymer selected from polyvinyl chloride, polyvinylidene chloride,
chlorinated polyolefins, and copolymers of vinyl chloride with
vinylidene chloride, vinyl acetate, vinyl propionate, vinyl
butyrate, vinyl benzoate, methyl acrylate, ethyl acrylate, and
butyl acrylate, and at least one primary plasticizer, and an alkyl
benzoate and, where appropriate, other additives, wherein isononyl
benzoate is present as alkyl benzoates in the composition. The
amount of all of the plasticizers present is from 10 to 400 parts
by weight, based on 100 parts by weight of polymers and the
proportion of the isononyl benzoate is from 5 to 95% by weight of
the total amount of the plasticizers.
[0017] The present invention also provides the use of compositions
of the invention for producing foamed products where the foamed
products comprise at least one polymer selected from polyvinyl
chloride, polyvinylidene chloride, chlorinated polyolefins, and
copolymers of vinyl chloride with vinylidene chloride, vinyl
acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, methyl
acrylate, ethyl acrylate, and butyl acrylate, and further comprise
at least one primary plasticizer, an isononyl benzoate, and, where
appropriate, other additives.
[0018] The invention also provides a process for producing products
which have at least one foamed polymer layer selected from the
following polymers: polyvinyl chloride, polyvinylidene chloride,
chlorinated polyolefins and copolymers of vinyl chloride with
vinylidene chloride, vinyl acetate, vinyl propionate, vinyl
butyrate, vinyl benzoate, methyl acrylate, ethyl acrylate, and
butyl acrylate, which includes applying a composition according to
the invention to a backing or a further polymeric layer and foaming
the composition prior to or after application and finally using
heat to process the applied and foamed layer. The present invention
also provides products which comprise at least one polymer selected
from polyvinyl chloride, polyvinylidene chloride, chlorinated
polyolefins and copolymers of vinyl chloride with vinylidene
chloride, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl
benzoate, methyl acrylate, ethyl acrylate, and butyl acrylate.
[0019] An advantage of the composition of the invention is that the
marked rises in viscosity at relatively high shear rates (known as
dilatancy) found when processing prior-art compositions (e.g.
blends of glycol dibenzoates) are avoided, or are found only to a
markedly lower extent, during the processing of compositions of the
invention, either for the production of chemical foams or else for
the production of mechanical foams.
[0020] The compositions of the invention not only have low
viscosity, even after prolonged storage, but also gel more rapidly
and have good low-temperature flexibility. In comparison with
conventional foamable compositions which may comprise, for example,
benzyl butyl phthalate, diisobutyl phthalate, or glycol dibenzoates
as plasticizers, foamability is also found to be better (e.g.,
lower foam densities).
DETAILED DESCRIPTION OF THE INVENTION
[0021] Some of the compositions of the invention and the processes
of the invention are described below by way of example. There is no
intention that the invention be restricted to these
embodiments.
[0022] In the foamable compositions of the invention comprising at
least one polymer selected from polyvinyl chloride, polyvinylidene
chloride, chlorinated polyolefins, and copolymers of vinyl chloride
with vinylidene chloride, vinyl acetate, vinyl propionate, vinyl
butyrate, vinyl benzoate, methyl acrylate, ethyl acrylate, and
butyl acrylate, at least one primary plasticizer is present, and
where appropriate, the composition may comprise other additives.
The compositions comprise isononyl benzoate and the amount of all
of the plasticizers present is from 10 to 400 parts by weight,
based on 100 parts by weight of polymers. The proportion of the
isononyl benzoate is from 5 to 95% by weight of the total amount of
the plasticizers. It can be advantageous for the proportion of a
mixture of one or more primary plasticizers and isononyl benzoate
to be present in the composition in an amount of from 15 to 200
parts by weight, preferably from 20 to 100 parts by weight, based
on 100 parts by weight of polymer. It can also be advantageous for
the plasticizer mixture itself to comprise from 10 to 70% by
weight, preferably from 10 to 50% by weight, of isononyl
benzoate.
[0023] The composition of the invention preferably comprises an
isomeric mixture of isononyl benzoates, derived from nonyl alcohols
obtained by saponifying the isomeric isononyl benzoates. The
mixture of isononyl benzoates is preferably derived from a mixture
of alcohols comprising less than 10 mol % of
3,5,5-trimethylhexanol. The method for saponifying the benzoic
esters and, respectively, the other esters mentioned below, may be
one of the usual methods such as reaction with alkaline media (see
by way of example Ullmann's Enzyklopdie der Technischen Chemie
[Ullmann's Encyclopedia of Industrial Chemistry], 5th edn. A 10,
pp. 254-260 incorporated herein by reference).
[0024] Examples of the foamable compositions of the invention
include plastisols. Among the abovementioned polymers, preference
is given to those which permit the preparation of plastisols. A
composition of the invention particularly preferably comprises one
or more grades of PVC which have been prepared by the emulsion
polymerization process, (e.g., emulsion PVC or E-PVC). A
composition of the invention very particularly preferably comprises
E-PVC whose molecular weight, stated as K value (Fikentscher
constant) is from 60 to 90, and particularly preferably from 65 to
85.
[0025] As primary plasticizers, the compositions of the invention
may comprise one or more of the compounds listed below, e.g.
dialkyl phthalates, having an alkyl radical containing from 4 to 13
carbon atoms, alkyl adipates having an alkyl radicals containing
from 4 to 13 carbon atoms, and/or alkyl cyclohexanedicarboxylates
having an alkyl radical containing from 4 to 13 carbon atoms,
trimellitic esters having from 7 to 10 carbon atoms in the alcohol
chain, alkylsulfonic esters derived from phenol, polymeric
plasticizers, alkyl benzyl phthalates, e.g. butyl benzyl phthalates
or octyl benzyl phthalates, dibenzoic esters of in particular,
diethylene glycol, dipropylene glycol or triethylene glycol, and/or
citric esters.
[0026] Among this list of the preferred primary plasticizers,
particular preference is given to those listed below.
[0027] Among the dialkyl phthalates, particular preference is given
to those whose alkyl radicals have from 4 to 11 carbon atoms. It is
unimportant here whether the alkyl radicals are identical or
different and/or linear or branched. Dialkyl phthalates
particularly preferred here are diisobutyl phthalate (DIBP),
di-n-butyl phthalate (DBP), benzyl n-butyl phthalate (BBP),
diisopentyl phthalate (DIPP), diisoheptyl phthalate (DIHP),
di-2-ethylhexyl phthalate (DEHP), diisooctyl phthalate (DIOP),
diisononyl phthalate (DINP), diisodecyl phthalate (DIDP),
di-2-propylheptyl phthalate (DPHP), diisoundecyl phthalate (DIUP),
di-C.sub.8-C.sub.10-alkyl phthalate, di-C.sub.7-C.sub.9-alkyl
phthalate, di-C.sub.7-C.sub.1-alkyl phthalate,
di-C.sub.9-C.sub.11-alkyl phthalate, and/or
di-C.sub.6-C.sub.10-alkyl phthalate.
[0028] Among the cyclohexanedicarboxylic esters, preference is
given to those whose alkyl radicals have from 7 to 11 carbon atoms.
It is likewise unimportant here whether the alkyl radical are
identical or different and/or linear or branched, or what cis-trans
ratio pertains between the ester groups. Particularly preferred
cyclohexanedicarboxylic esters are diisoheptyl
1,2-cyclohexanedicarboxylate, di-2-ethylhexyl
1,2-cyclohexanedicarboxylate, diisononyl
1,2-cyclohexanedicarboxylate, diisodecyl
1,2-cyclohexanedicarboxylate, di-2-propylheptyl
1,2-cyclohexanedicarboxylate, diisoheptyl
1,4-cyclohexanedicarboxylate, di-2-ethylhexyl
1,4-cyclohexanedicarboxylate, diisononyl
1,4-cyclohexanedicarboxylate, diisodecyl
1,4-cyclohexanedicarboxylate, and/or di-2-propylheptyl
1,4-cyclohexanedicarboxylate.
[0029] In the case of the trimellitic esters (e.g.,
1,2,4-benzenetricarboxylic esters) having from 7 to 10 carbon atoms
in the alcohol chain, it is again unimportant whether the alkyl
radicals are identical or different and/or linear or branched.
Particularly preferred trimellitic esters are tri-2-ethylhexyl
trimellitate, triisononyl trimellitate, triisodecyl trimellitate,
tri-2-propylheptyl trimellitate, tri-C.sub.7-C.sub.9-alkyl esters
and/or, tri-C.sub.8-C.sub.10-alkyl esters.
[0030] Citric esters present in the compositions of the invention
may preferably include those having from 2 to 10 carbon atoms in
the alcohol chains, in each case with or without a carboxylated OH
group. It is unimportant whether the alkyl radicals are identical
or different, linear or branched. Particular preference is given to
tributyl acetylcitrate, tri-2-ethylhexyl citrate, tri-2-ethylhexyl
acetylcitrate, triisononyl acetylcitrate, triisononyl citrate,
tri-n-butyl citrate, tri-C.sub.6-C.sub.10-alkyl citrate,
tri-n-hexyl butyrylcitrate as citric esters in the composition of
the invention.
[0031] In the case of adipic esters having from 4 to 13 carbon
atoms in the alcohol chain it is again unimportant whether the
alkyl radicals are identical or different and/or linear or
branched. Dibutyl adipate, di-2-ethylhexyl adipate, diisononyl
adipate, diisodecyl adipate, di-2-propylheptyl adipate,
diisotridecyl adipate are particularly preferably present as adipic
esters in the composition of the invention.
[0032] As dibenzoic esters, the composition of the invention
preferably comprises alkylenediol dibenzoates, and, in particular,
glycol dibenzoates, such as diethylene glycol dibenzoate,
dipropylene glycol dibenzoate, diisopropylene glycol dibenzoate,
dibutylene glycol dibenzoate, tripropylene glycol dibenzoate,
triethylene glycol dibenzoate, or a mixture composed of two or more
of these compounds.
[0033] A composition of the invention particularly preferably
comprises, as primary plasticizer, an alkyl phthalate, with
preference diisononyl phthalate (DINP), diisoheptyl phthalate
(DIHP), diisodecyl phthalate (DIDP), di-2-propylheptyl phthalate
(DPHP) and/or di-2-ethylhexyl phthalate (DEHP), an alkyl
cyclohexanedicarboxylate, preferably diisononyl
cyclohexanedicarboxylate (DINCH), and/or an alkyl adipate,
preferably diisononyl adipate (DINA), and/or di-2-ethylhexyl
adipate (DEHA).
[0034] Clearly, the compounds mentioned and present as primary
plasticizers in the composition may include commercially available
products. For example, the compositions of the invention may
comprise, as benzoates, the commercial products K-flex (Kalama
Chem; by way of example the product grades DP, DE and 500) or
Benzoflex (Velsicol; by way of example the product grades 9-88,
2-45, 50, 2088), which can be prepared from the raw materials
benzoic acid, diethylene glycol, dipropylene glycol, and
triethylene glycol. Phthalates which may be used in the
compositions of the invention are the industrial phthalates
obtainable by way of example with the tradenames Vestinol C
(di-n-butyl phthalate) (CAS No.84-74-2), Vestinol IB (di-1-butyl
phthalate) (CAS No. 84-69-5), Jayflex DINP (CAS No.68515-48-0),
Jayflex DIDP (CAS No.68515-49-1), Palatinol 9P (68515-45-7),
Vestinol 9 (CAS No. 28553-12-0), TOTM (CAS No. 3319-31-1), Linplast
68-TM, Palatinol N (CAS No. 28553-12-0), Jayflex DHP (CAS No.
68515-50-4), Jayflex DIOP (CAS No. 27554-26-3), Jayflex UDP (CAS
No. 68515-47-9), Jayflex DIUP (CAS No. 85507-79-5), Jayflex DTDP
(CAS No.68515-47-9), Jayflex L9P (CAS No. 68515-45-7), Jayflex
L911P (CAS No. 68515-43-5), Jayflex L11P (CAS No. 3648-20-2),
Witamol 110 (CAS No. 68515-51-5), Witamol 118
(di-n-C.sub.8-C.sub.10-alkyl phthalate) (CAS No.71662-46-9),
Unimoll BB (CAS No. 85-68-7), Linplast 1012 BP (CAS No.
90193-92-3), Linplast 13XP (CAS No.27253-26-5), Linplast 610P (CAS
No. 68515-51-5), Linplast 68 FP (CAS No. 68648-93-1), Linplast 812
HP (CAS No. 70693-30-0), Palatinol AH (CAS No. 117-81-7), Palatinol
711 (CAS No. 68515-42-4), Palatinol 911 (CAS No. 68515-43-5),
Palatinol 11 (CAS No. 3648-20-2), Palatinol Z (CAS No.26761-40-0),
Palatinol DIPP (CAS No. 84777-06-0), Jayflex 77 (CAS No.
71888-89-6), Palatinol 10 P (CAS No. 53306-54-0) or Vestinol AH
(CAS No. 117-81-7). "CAS No." means Chemical Abstracts Registry
Number. It is, of course, also possible to use mixtures of two or
more of these commercially available products as primary
plasticizers in the composition of the invention.
[0035] Besides the compounds mentioned immediately above, which may
be present as primary plasticizers in the composition of the
invention, it is also possible for polymeric plasticizers based on
dicarboxylic acids, such as adipic or phthalic acid, and on
polyhydric alcohols to be present as primary plasticizers in the
composition of the invention.
[0036] The foamable composition of the invention may comprise, as
additives, for example, at least one selected from the group of
filler, pigment, heat stabilizer, antioxidant, viscosity regulator,
foam stabilizer, and/or lubricant.
[0037] One of the functions of the heat stabilizers is to
neutralize hydrochloric acid eliminated during and/or after the
processing of the PVC, and to inhibit thermal degradation of the
polymer. The heat stabilizers may be any conventional PVC
stabilizers in solid or liquid form, for example those based on
Ca/Zn, on Ba/Zn, on Pb, on Sn, or on organic compounds (OBSs), and
also acid-binding phyllosilicates, such as hydrotalcite. The
mixtures of the invention may have from 0.5 to 10 parts by weight,
preferably from 1 to 5 parts by weight, particularly preferably
from 1.5 to 4 parts by weight of the heat stabilizer per 100 parts
by weight of polymer.
[0038] For the purposes of the present invention, pigments which
may be used comprise not only inorganic but also organic pigments.
The content of pigments is from 0.01 to 10% by weight, preferably
from 0.05 to 5% by weight, particularly preferably from 0.1 to 3%
by weight. Examples of inorganic pigments are CdS,
CoO/Al.sub.2O.sub.3, Cr.sub.2O.sub.3. Known organic pigments by way
of example are azo colorants, phthalocyanine pigments, dioxazine
pigments, and aniline pigments.
[0039] Viscosity-lowering reagents which may be used comprise
aliphatic or aromatic hydrocarbons, but also carboxylic acid
derivatives, e.g. 2,2,4-trimethyl-1,3-pentadiol diisobutyrate,
known as TXIB (Eastman). The latter may also readily be replaced by
isononyl benzoate, because intrinsic viscosity is similar. The
proportions of viscosity-lowering reagents added are from 0.5 to 50
parts by weight, preferably from 1 to 30 parts by weight,
particularly preferably from 2 to 10 parts by weight, per 100 parts
by weight of polymer.
[0040] Foam stabilizers which may be present in the composition of
the invention may include commercially available foam stabilizers.
By way of example, these foam stabilizers may include
silicone-based or soap-based stabilizers, and such as tradenames
BYK (Byk-Chemie) and SYNTHAMID (Th. Boehme GmbH), for example. The
amounts of these present in an invention composition may be from 1
to 10 parts by weight, preferably from 1 to 8 parts by weight,
particularly preferably from 2 to 4 parts by weight, per 100 parts
by weight of polymer.
[0041] Depending on whether the foamable composition is intended to
be foamed chemically or mechanically, the composition may further
comprise one or more components which generate gas, in the form of,
for example, bubbles and may optionally comprise a kicker defined
below. The foamable component preferably comprises a compound which
decomposes on exposure to heat to give predominantly gaseous
constituents which bring about expansion of the composition. One
typical representative of these compounds, by way of example, is
azodicarbonamide. The decomposition temperature of the blowing
agent may be reduced markedly in the presence of catalysts in the
composition of the invention. These catalysts are known as
"kickers" to the person skilled in the art, and may be added either
separately or preferably in the form of a single system with the
stabilizer.
[0042] The preparation of the isononyl benzoate present in the
composition of the invention is described below. The product that
may be used for preparing the isononyl benzoate is a mixture of
isomeric nonyl alcohols and benzoic acid. The mixture of isomeric
nonyl alcohols used to prepare the isononyl benzoate is often
termed isononanol. The mixtures (e.g. isononanols) preferably have
high linearity characterized by a proportion of less than 10 mol %
(from 0 to 10), preferably less than 5 (from 0 to 5) mol %,
particularly preferably less than 2 (from 0 to 2) mol %, of
3,5,5-trimethylhexanol. The isomeric distribution of nonyl alcohol
mixtures is determined by the manner of preparation of the nonyl
alcohol (isononanol). The isomeric distributions of the nonyl
radicals may be determined using conventional measurement methods
familiar to the person skilled in the art, e.g. NMR spectroscopy,
or GC or GC/mass spectroscopy. These properties made here relate to
all of the nonyl alcohol mixtures mentioned below. These nonyl
alcohols (e.g., nonyl alcohol mixtures) include commercially
available mixtures with CAS numbers 27458-94-2, 68515-81-1,
68527-05-9 or 68526-84-1.
[0043] Isononanol may be prepared by hydroformylating octenes,
which in turn are produced in various ways. Industrial C.sub.4
streams may be used as the raw material for this purpose and
initially comprise all of the isomeric C.sub.4 olefins alongside
the saturated butanes and sometimes contamination, such as C.sub.3
and C.sub.5 olefins and acetylenic compounds. Oligomerization of
this olefin mixture predominantly gives isomeric octene mixtures
alongside higher oligomers, such as C.sub.12 and C.sub.16 olefin
mixtures. These octene mixtures are hydroformylated to give the
corresponding aldehydes, and then hydrogenated to give the
alcohol.
[0044] The constitution, i.e. the isomeric distribution, of the
industrial nonanol mixtures depends on the starting material and on
the oligomerization and hydroformylation processes. Any of these
mixtures may be used to prepare the esters of the invention.
Preferred nonanol mixtures are those which have been obtained by
hydroformylating C.sub.8 olefin mixtures obtained by oligomerizing
substantially linear butenes on nickel support catalysts (e.g.
OCTOL process, OXENO Olefinchemie GmbH), in the presence of known
catalysts, e.g. Co compounds or Rh compounds, and then
hydrogenating the hydroformylation mixture after catalyst removal.
The proportion of isobutene in the starting material, based on the
total butene content, is less than 5% by weight, preferably less
than 3% by weight, particularly preferably less than 1% by weight.
As a result of this, the proportion of relatively highly branched
nonanol isomers, including that of 3,5,5-trimethylhexanol, which
has not proven to be particularly advantageous, is markedly
suppressed and is within the preferred ranges.
[0045] The composition of the invention may also comprise isononyl
benzoates which are obtained by esterifying benzoic acid with a
commercially available alcohol mixture which may by way of example
have the CAS numbers 68551-09-7, 91994-92-2, 68526-83-0,
66455-17-2, 68551-08-6, 85631-14-7 or 97552-90-4. These are alcohol
mixtures which comprise not only the isononyl alcohols mentioned
but also alcohols having from 7 to 15 carbon atoms (in accordance
with CAS definition). The result is therefore alkyl benzoate
mixtures which comprise not only isononyl benzoate but also other
alkyl esters of benzoic acid.
[0046] The preparation of isononyl benzoate, i.e. the
esterification of benzoic acid with an isomerically pure nonanol or
with an isononanol mixture to give the corresponding esters, may be
carried out autocatalytically or catalytically, for example using
Bronstedt or Lewis acids. Quite irrespective of the type of
catalysis selected, the result is always a temperature-dependent
equilibrium between the starting materials (acid and alcohol) and
the products (ester and water). In order to shift the equilibrium
in favor of the ester, use may be made of an entrainer, which
allows removal of the water produced by the reaction. Since the
alcohol mixtures used for esterification have lower boiling points
than the benzoic acid and its esters and have a region of
immiscibility with water, they are often used as entrainer which
can be returned to the process after removal of water.
[0047] The alcohol or, respectively, the isomeric alcohol mixture
used to form the ester and simultaneously act as entrainer is used
in excess, this preferably being from 5 to 50%, in particular from
10 to 30%, in addition to the amount needed to form the ester.
[0048] Esterification catalysts which may be used are acids, such
as sulfuric acid, methane sulfonic acid, or p-toluenesulfonic acid,
or metals, or their compounds. Examples of those suitable are tin,
titanium, and zirconium, and these may be used in the form of
finely divided metals, or advantageously in the form of their
salts, oxides, or soluble organic compounds. Unlike protonic acids,
the metal catalysts are high-temperature catalysts whose full
activity is often not achieved until temperatures reach above
180.degree. C. However, their use is preferred since the level of
formation of by-products, such as olefins from the alcohol used, is
lower when comparison is made with protonic catalysis. Examples
representing metal catalysts are tin powder, stannous oxide,
stannous oxalate, titanium esters, such as tetraisopropyl
orthotitanate or tetrabutyl orthotitanate, and zirconium esters,
such as tetrabutyl zirconate.
[0049] The concentration of catalyst depends on the nature of the
catalyst. In the case of the titanium compounds whose use is
preferred, it is from 0.005 to 1.0% by weight, based on the
reaction mixture, in particular from 0.01 to 0.5% by weight, very
particularly from 0.01 to 0.1% by weight.
[0050] When titanium catalysts are used, the reaction temperatures
are from 160 to 270.degree. C., preferably from 180 to 250.degree.
C. The ideal temperatures depend on the starting materials, the
progress of the reaction, and the concentration of catalyst. They
may readily be determined by trials for each individual case.
Higher temperatures increase the reaction rates and favor side
reactions, such as elimination of water from alcohols or formation
of colored by-products. For removal of the water of reaction, it is
advantageous that the alcohol can be distilled off from the
reaction mixture. The desired temperature or the desired
temperature range may be set via the pressure in the reaction
vessel. For this reason, the reaction is carried out at
superatmospheric pressure in the case of low-boiling alcohols, and
at subatmospheric pressure in the case of relatively high-boiling
alcohols. For example, operations for the reaction of benzoic acid
with a mixture of isomeric nonanols are carried out in a range of
temperature from 170 to 250.degree. C. in the range of pressures
from 1 bar to 10 mbar.
[0051] Some or all of the liquid to be returned to the reaction may
be composed of alcohol obtained by work-up of the azeotropic
distillate. It is also possible to carry out the work-up at a later
juncture, and to replace some or all of the amount of liquid
removed by fresh alcohol, i.e. alcohol provided in a feed
vessel.
[0052] The crude ester mixtures, which comprise by-products as well
as the ester(s), alcohol, and catalyst or products derived from the
catalyst, are worked up by processes known per se. This work-up
encompasses the following steps: removal of the excess alcohol and,
where appropriate, low-boilers, neutralization of the acids
present, and optional steam distillation, conversion of the
catalyst into a residue which is easy to filter, removal of the
solids, and, where appropriate, drying. The sequence of these steps
may differ, depending on the work-up process used.
[0053] The nonyl ester or the mixture of the nonyl esters may be
removed from the reaction mixture by distillation, where
appropriate after neutralization of the mixture.
[0054] As an alternative, the nonyl benzoates of the invention may
be obtained by transesterifying a benzoic ester with nonanol or
with an isononanol mixture. The starting materials used comprise
benzoic esters whose alkyl radicals bonded to the O atom of the
ester group contain from 1 to 8 carbon atoms. These radicals may be
aliphatic, straight-chain or branched, alicyclic, or aromatic. One
or more methylene groups in these alkyl radicals may be substituted
by oxygen. It is advantageous that the alcohols on which the
starting ester is based have lower boiling points than the
isononanol mixture or nonanol used. Preferred starting materials
for the transesterification are methyl benzoate, ethyl benzoate,
propyl benzoate, isobutyl benzoate, n-butyl benzoate and/or pentyl
benzoate.
[0055] The transesterification is carried out catalytically, for
example using Bronstedt or Lewis acids, or using bases. Quite
irrespective of the catalyst used, the result is always a
temperature-dependent equilibrium between the starting material
(alkyl benzoate and isononanol mixture or nonanol) and the products
(nonyl ester or nonyl ester mixture and liberated alcohol). In
order to shift the equilibrium in favor of the nonyl ester or of
the isononyl ester mixture, the alcohol produced from the starting
ester is distilled off from the reaction mixture.
[0056] Here, too, it is advantageous to use excess of the
isononanol mixture or, respectively, nonanol.
[0057] Transesterification catalysts which may be used are acids,
such as sulfuric acid, methanesulfonic acid, or p-toluene sulfonic
acid, or metals or their compounds. Examples of those suitable are
tin, titanium, and zirconium, these being used in the form of
finely divided metals, or advantageously in the form of their
salts, oxides, or soluble organic compounds. Unlike protonic acids,
the metal catalysts are high-temperature catalysts whose full
activity is often not achieved until temperatures reach above
180.degree. C. However, their use is preferred since the level of
formation of by-products, such as olefins from the alcohol used, is
lower when comparison is made with protonic catalysis. Examples
representing metal catalysts are tin powder, stannous oxide,
stannous oxalate, titanium esters, such as tetraisopropyl
orthotitanate or tetrabutyl orthotitanate, and zirconium esters,
such as tetrabutyl zirconate.
[0058] Use may also be made of basic catalysts, such as oxides,
hydroxides, hydrogen carbonates, carbonates, or alkoxides of alkali
metals or of alkaline earth metals. Among this group, preference is
given to using alkoxides, such as sodium methoxide. It is also
possible to prepare alkoxides in situ from an alkali metal and an
isonanol mixture or, respectively, a nonanol.
[0059] The concentration of catalyst depends on the nature of the
catalyst. It is usually from 0.005 to 1.0% by weight, based on the
reaction mixture.
[0060] The reaction temperatures for transesterification are
usually from 100 to 220.degree. C. They have to be at least high
enough to permit the alcohol produced from the starting ester to be
distilled off from the reaction mixture at the prevailing pressure,
mostly atmospheric pressure.
[0061] The work-up of the transesterification mixtures may be the
same as described for the esterification mixtures.
[0062] There are various methods for preparing the compositions of
the invention. The compositions are generally prepared by intimate
mixing of all of the components in a suitable mixing container. In
this process, the components are preferably added in succession
(e.g. E. J. Wickson, "Handbook of PVC Formulating", John Wiley and
Sons, 1993, p. 727, incorporated herein by reference).
[0063] The compositions of the invention may be used to produce
foamed products which comprise at least one polymer selected from
polyvinyl chloride, polyvinylidene chloride, chlorinated
polyolefins and copolymers of vinyl chloride with vinylidene
chloride, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl
benzoate, methyl acrylate, ethyl acrylate, butyl acrylate, and
comprise at least one primary plasticizer, isononyl benzoate, and,
where appropriate, other additives. By way of example, these
products may be synthetic leather, wallcoverings, or the various
foam layers for floorcoverings (cushion vinyl foam or foam
backing).
[0064] The compositions of the invention are preferably used to
prepare plastisols, in particular to prepare PVC plastisols, with
particularly advantageous processing properties. These foamable
plastisols may be used in a wide variety of products, such as
synthetic leather, floorcoverings, wallcoverings, etc. Among these
applications, particular preference is given to the use in cushion
vinyl (CV) floorcoverings. Use of the compositions of the invention
as a mixing specification constituent or directly in the form of
plastisols can give plastisols with low viscosity and with
increased storage stability, and at the same time with faster
gelling and improved low-temperature flexibilization.
[0065] The process of the invention for producing products which
have a foamed polymer layer selected from the following polymers:
polyvinyl chloride, polyvinylidene chloride, chlorinated
polyolefins and copolymers of vinyl chloride with vinylidene
chloride, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl
benzoate, methyl acrylate ethyl acrylate, butyl acrylate, includes
applying a composition of the invention to a backing or a further
polymeric layer and foaming prior to or after application, and
finally heating to process the composition.
[0066] The foaming may take place mechanically or chemically. The
expression mechanical foaming of a composition or a plastisol means
that sufficiently vigorous agitation is used to introduce air into
the plastisol prior to application to the backing, and that the
entrained air results in foaming. A stabilizer may be needed to
stabilize the resultant foam. Use is generally made of systems
based either on silicone or on soaps. These differ in respect of
the finished foam, primarily in cell structure, color, and water
absorption performance. The selection of the stabilizer type
depends inter alia on the plasticizers intended for use. For
example, it is known to the person skilled in the art that when use
is made of the relatively low-price foam stabilizers based on soaps
it is necessary to add sufficiently large amounts of benzyl
phthalate (e.g. BBP) or of glycol dibenzoates to the dialkyl
phthalates usually used, for example DEHP, DINP, DIDP, or DIHP.
Because the use of BBP is reducing markedly in recent times as a
result of its imminent classification in chemicals legislation
("toxic"), glycol dibenzoates are often used as replacement
materials. The term glycol dibenzoates includes diethylene glycol
dibenzoate (DEGDB), triethylene glycol dibenzoate (TEGDB) and
dipropylene glycol dibenzoate (DPGDB), or a mixture of these. These
products are commercially available by way of example with the
tradename "Benzoflex" from Velsicol, USA. Benzoflex 2088 (according
to manufacturer's information from 61 to 69% of DEGDB, from 16 to
24% of DPGDB, from 11 to 19% of TPGDB) and Benzoflex 2160
(according to the manufacturer's information 49% of DEGDB, 29% of
TEGDB, 15% of di-2-ethylhexyl adipate, inter alia) have achieved
some significance as blends of glycol dibenzoates in the PVC
floorcovering sector. However, these products have a strong
dilatent tendency, i.e. tend to give a marked rise in viscosity at
relatively high shear rates, a possible result being problems
during processing. Blends of these glycol dibenzoates with isononyl
benzoate can very substantially compensate for this disadvantage.
Foamable compositions of the invention intended for use for
producing mechanical foams may therefore comprise glycol
dibenzoates alongside isononyl benzoate. The foamed composition is
then applied to the backing or to another polymer layer, and is
finally treated with heat. Examples of commercially available foam
stabilizers based on soaps include BYK 8070 (Byk-Chemie) and
SYNTHAMID 218 (Th. Boehme GmbH). BYK 8020 (Byk-Chemie) is a widely
used silicone-based system.
[0067] In the case of chemical foaming, the plastisol or the
composition of the invention comprises a compound known as a
blowing agent which, when exposed to heat, decomposes to give
predominantly gaseous constituents which bring about expansion of
the plastisol. One typical representative is azodicarbonamide. The
decomposition temperature of the blowing agent may be markedly
reduced by adding catalysts. These catalysts are familiar as
"kickers" to the person skilled in the art, and may be added either
separately or preferably in the form of a single system with the
heat stabilizer. Unlike in the case of the mechanical foam, it is
possible, where appropriate, to omit a foam stabilizer. Unlike in
mechanical foaming, in chemical foaming the foam is not formed
until processing begins, generally in a gelling tunnel, and this
means that the as yet unfoamed composition is applied to the
backing, preferably by spreading. In this embodiment of the process
of the invention, it is possible to profile the foam by selective
application of inhibitor solutions, for example by way of a rotary
screen printing system. At the sites where the inhibitor solution
has been applied, no expansion, or only retarded expansion, of the
plastisol takes place during processing. Industry uses chemical
foaming to a much greater extent than mechanical foaming. Further
information concerning chemical and mechanical foaming may be found
by way of example in E. J. Wickson, "Handbook of PVC Formulating",
1993, John Wiley & Sons (incorporated herein by reference in
its entirety).
[0068] In the case of both processes, the backing materials used
may comprise those which remain firmly bonded to the resultant
foam, e.g. woven or nonwoven webs. However, the backing materials
may also be merely temporarily backing materials, from which the
resultant foams can in turn be removed in the form of foam layers.
Examples of these backing materials may be metal belts or release
paper (Duplex paper). Another polymer layer, where appropriate one
which has previously been completely or partially gelled (e.g.,
pre-gelled), may also function as a backing. This method is used in
particular for CV floorcoverings whose structure is composed of a
plurality of layers.
[0069] In both cases, the final treatment with heat takes place in
what is known as a gelling tunnel, generally an oven, through which
a layer applied to the backing and composed of or containing the
composition of the invention is passed, or into which the backing
with the layer is introduced for a short period. The final
treatment with heat serves to solidify (gel) the foamed layer. In
the case of chemical foaming, the gelling tunnel may be combined
with an apparatus serving to produce the foam. For example, it is
possible to use only one gelling tunnel, in the upstream portion of
which, at a first temperature, the foam is produced chemically by
decomposition of a gas-forming component, this foam being converted
in the downstream portion of the gelling tunnel, at a second
temperature which is preferably higher than the first temperature,
into the semifinished or finished product. Depending on the
composition, it is also possible for gelling and foam-formation to
take place simultaneously at a single temperature. Typically
processing temperatures (gelling temperatures) are in the range
from 130 to 280.degree. C., preferably in the range from 150 to
250.degree. C. In the preferred manner of gelling, the foamed
composition is treated at the gelling temperatures mentioned for a
period of from 0.5 to 5 minutes, preferably for a period of from
0.5 to 3 minutes. In the case of processes which operate
continuously, the duration of the heat treatment here may be
adjusted via the length of the gelling tunnel and the velocity with
which the backing, on which the foam is applied, passes through the
same. Typical foam-formation temperatures (chemical foam) are in
the range from 160 to 240.degree. C., preferably from 180 to
220.degree. C.
[0070] In the case of multilayer systems, the shape of the
individual layers is generally first fixed by what is known as
pre-gelling of the applied plastisol at a temperature below the
decomposition temperature of the blowing agent, and after this
other layers (e.g. a top layer) may be applied. Once all of the
layers have been applied, a higher temperature is used for the
gelling processes--and also for the foam-forming process in the
case of chemical foaming. The desired profiling can also be
extended to the top layer by this procedure.
[0071] By way of the compositions of the invention, and of the
process of the invention, it is possible to produce products which
comprise at least one polymer selected from polyvinyl chloride,
polyvinylidene chloride, chlorinated polyolefins and copolymers of
vinyl chloride with vinylidene chloride, vinyl acetate, vinyl
propionate, vinyl butyrate, vinyl benzoate, methyl acrylate, ethyl
acrylate, butyl acrylate, and which comprise foamed layers of a
composition of the invention. Examples of these products may be
floorcoverings, wallcoverings, or synthetic leather.
[0072] The examples below are intended to illustrate the invention
without restricting the breadth of application that is apparent
from the description and from the claims.
EXAMPLE 1
[0073] Preparation of Isononyl Benzoate
[0074] 976 g of benzoic acid (8 mol), 1728 g of isononanol from
OXENO Olefinchemie GmbH (12 mol), and 0.59 g of butyl titanate
(0.06%, based on the amount of acid) were weighed in a 4 liter
distillation flask on which there is a water separator and reflux
condenser, and also a sampling stub and thermometer, and were
heated to boiling under nitrogen. The water produced during the
esterification reaction was removed regularly. When (after about 3
hours) the acid value fell below 0.1 mg KOH/g, the mixture was
first cooled below 60.degree. C., and a 20 cm multifill column was
superposed. The pressure was then reduced to 2 mbar, and the excess
alcohol was then distilled off (about 120.degree. C.). After
removal of an intermediate fraction at up to 140.degree. C., the
isononyl benzoate could be distilled over in the range from 142 to
147.degree. C. (at 2 mbar), measured at the head of the column. The
purity determined by gas chromatography was >99.7%. The
viscosity of the product at 20.degree. C. was determined to DIN 53
015 as 8.4 mPa.multidot.s.
EXAMPLE 2
[0075] Preparation of Plastisols for Chemical Foam (CV Foam)
[0076] The starting weights of the components are given in the
table below.
1TABLE 1 Mixing specifications (all data in phr (= parts by weight
per 100 parts of PVC)) 4 5 (Top 1 2 3 inventive Layer) VESTOLIT
P1352 80 80 80 80 K (Vestolit) VESTOLIT P1430 80 K90 (Vestolit)
VINNOLIT C65V (Vinnolit) 20 20 20 20 20 VESTINOL AH (DEHP, 35
OXENO) VESTINOL 9 (DINP, 40 40 40 40 12 OXENO) Unimoll BB (BBP,
Bayer) 17 Diisobutyl phthalate 17 (DIBP, OXENO) Benzoflex 2088
(Velsicol) 17 Isononyl benzoate (INB) 17 Lankroflex ED 6 (Akcros) 3
Baerostab CT 9156 1.5 X (Baerlocher) Porofor ADC/L-C2 4 4 4 4 (1:1)
(Bayer) Bayoxid Z Aktiv (1:2) (Bayer) 1.5 1.5 1.5 1.5 Kronos 2220
(titanium 5 5 5 5 dioxide, Kronos) Durcal 5 (chalk, Omya) 10 10 10
10
[0077] The plasticizers were brought to a temperature at 25.degree.
C. prior to addition. The liquid constituents were weighed first
into a PE beaker and were followed by the pulverulent constituents.
The mixture was mixed manually using a paste spatula until all the
powder had been wetted. The mixing beaker was then clamped into the
clamping equipment of a dissolver mixer. Prior to immersing the
stirrer into the mixture, the rotation rate was set at 1 800
revolutions per minute. Once the stirrer had been switched on,
stirring was continued until the temperature on the digital display
of the temperature sensor reached 30.0.degree. C. This ensured that
the plastisol was homogenized with defined energy input. The
temperature of the plastisol was then immediately brought to
25.0.degree. C.
EXAMPLE 3
[0078] Testing of Plastisol Viscosities
[0079] The viscosities of plastisols 1 to 4 prepared in example 2
were measured as follows by a method based on DIN 53 019, using the
Physica DSR 4000 rheometer, controlled by US 200 software.
[0080] The plastisol was again stirred with a spatula in the
storage vessel, and was tested in accordance with the operating
instructions in test system Z3 (DIN 25 mm). Measurement proceeded
automatically at 25.degree. C. by way of the abovementioned
software. The settings were as follows:
[0081] pre-shear of 100 s.sup.-1 for a period of 60 s, during which
no values were measured,
[0082] a downward progression beginning at 200 s.sup.-1 and ending
at 0.1 s.sup.-1, divided into a logarithmic series with 30 steps,
the duration for each point of measurement being 5 s.
[0083] After the test, the test data were processed automatically
by the software. Viscosity was plotted as a function of shear rate.
Each of the measurements was made after 2 h and 24 h. Between these
junctures, the paste was stored at 25.degree. C.
[0084] The two tables below, Table 2 and Table 3, list the
viscosity values obtained after each of the storage times given for
shear rates of 10 s.sup.-1 and 100 S.sup.-1.
2TABLE 2 Shear rate 10 s.sup.-1 (viscosity data in Pa * s) Mixing
specification 4 1 2 3 (inventive) 2 h 3.9 3.9 3.8 2.7 24 h 5.2 5.0
4.8 3.1
[0085]
3TABLE 3 Shear rate 100 s.sup.-1 (viscosity data in Pa * s) Mixing
specification 4 1 2 3 (inventive) 2 h 4.3 3.9 4.5 2.1 24 h 5.7 5.2
5.7 2.6
[0086] On the basis of the measured values listed in Tables 2 and 3
it can be shown that the foam plastisols using isononyl benzoate
(mixing specification 4) differ substantially in their viscosity
behavior from the plastisols with identical proportions of BBP,
DIBP, or Benzoflex 2088. Because the viscosity of the plastisol of
the invention is lower, it is possible to omit, or at least reduce
the amount of, viscosity-lowering reagents, which are frequently
expensive.
EXAMPLE 4
[0087] Chemical Foaming at 200.degree. C.
[0088] A doctor is used to apply plastisols 1 to 4 prepared in
example 2 onto Kamplex LWB duplex paper (120 g/m.sup.2, Kmmerer),
to give an application rate of 360.+-.10 g/m.sup.2. For
drying/pre-gelling, this material is passed at 6 m/min through a
gelling tunnel (Olbrich, length 8 m) at a temperature of
130.degree. C. A similar procedure is then used in each case to
apply in top layer (mixing specification 5 from Table 1,
application rate 200+10 g/m.sup.2) to this layer. The
gelling/foaming process is then carried out at 200.degree. C. with
various residence times, set by way of the conveying speed of the
system. The thickness of each of the foamed layers was
measured.
[0089] The thicknesses of the resultant products can be used to
determine the foaming ratio in percent, based on the thickness of
the product which has been pregelled but not further processed.
Table 4 gives the foaming ratios for mixing specifications 1 to 4
after a residence time of 60, 80, 100, and 120 seconds.
4TABLE 4 Foaming ratios for mixing specifications 1 to 4 (data in
percent) Residence time (s) 60 80 100 120 Mixing specification 1
1.7 94.9 245.8 289.8 Mixing specification 2 0.0 77.6 237.9 291.4
Mixing specification 3 0.0 91.5 239.0 274.6 Mixing specification 4
0.0 62.1 246.6 317.2 (inventive)
[0090] Despite somewhat slower foaming of plastisol 4 of the
invention at a relatively low residence time of 80 s (in the middle
of the foaming process) it is apparent that at typical industrial
residence times of 100 s or above the comparable foaming ratios
that can be obtained are at least the same or indeed better.
EXAMPLE 5
[0091] Mechanical Foaming (Preparation of Plastisols)
[0092] The following plastisols were prepared using the overall
mixing specification given in Table 5 below:
5TABLE 5 Mixing specifications for plastisols for mechanical
foaming (data in phr) 6 7 8 9 VESTOLIT P1415K80 (Vestolit) 70 70 70
70 VINNOLIT C65V (Vinnolit) 30 30 30 30 VESTINOL 9 (OXENO) 30 30 30
30 Unimoll BB (BBP, Bayer) 30 Benzoflex 2088 (Velsicol) 30 20 15
Isononyl benzoate 10 15 Byk 8070 (Byk-Chemie) 2.6 2.6 2.6 2.6
Durcal 5 (chalk, Omya) 30 30 30 30
[0093] Once the plastisols have been prepared as in Example 2,
these are de-aerated at 20 mbar in order to remove any air
introduced by the mixing process. The de-aeration procedure is
simpler in all instances for the low-viscosity plastisols than for
those of higher viscosity.
[0094] As in Example 3, a Physica rheometer was likewise used to
determine the viscosities of plastisols 6 to 9 after 2 and 24 hours
at shear rates of 10 and 100 s.sup.-1, and these have been listed
in Tables 6 and 7.
6TABLE 6 Viscosities of plastisols at shear rate 10 s.sup.-1 in Pa
* s: 6 7 8 9 After 2 h 3.2 3.5 2.0 1.5 After 24 h 3.6 3.9 2.2
1.6
[0095]
7TABLE 7 Viscosities of plastisols at shear rate of 100 s.sup.-1 in
Pa * s: 6 7 8 9 After 2 h 3.9 4.8 2.5 1.9 After 24 h 4.4 5.4 2.8
2.0
[0096] Here again, the effect of rising content of isononyl
benzoate on the viscosity of the plastisols is discernible.
[0097] The behavior of the plastisol under conditions close to
production conditions is again tested in a gelling tunnel (Olbrich,
length 8 m). After pre-foaming by introducing air through nozzles,
with stirring, to give a wet foam density of 0.61 g/cm.sup.3, a
doctor (gap width 1.5 mm; doctor chamfer 9 mm, doctor angle
7.degree.) is used to apply the plastisol to Kamplex LWB duplex
paper (120 g/m.sup.2, Kmmerer), and it is then run at a pre-set
speed through the gelling tunnel.
[0098] If the residence time in the gelling tunnel is varied at a
processing temperature of 180.degree. C., it is possible to
determine the maximum processing or spreading speed which still
gives a stable foam. The homogeneity of the surface is decisive for
this assessment, and is evaluated visually. In addition, the foam
densities in the fully gelled final product were determined by
weighing and thickness measurement, using the residence time of 1.3
min which is typical for industrial purposes (corresponding here to
a speed of 6 m/min). The results are given in Table 8.
8TABLE 8 Results of processing 6 7 8 9 Max. spreading speed in 8 10
10 8 m/min. Foam density in g/cm.sup.3 0.60 0.65 0.58 0.56 after
1.3 min. of residence time (typical)
[0099] As can be seen from the results in Table 8, the plastisols
of the invention using isononyl benzoate (mixing specification 8 or
9) can be foamed to a greater extent at maximum spreading speeds
comparable with those for mixing specifications 6 and 7, this being
discernible from the lower density.
[0100] German application 10336150.2 filed on Aug. 7, 2003 is
incorporated herein by reference in its entirety.
[0101] Obviously, numerous modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *